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08-15-2009, 10:08 PM   #1
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Some more K2000 questions

First question is trap-focus. I could've sworn I had it working earlier but maybe or apparently it was with a different lens which was MF I borrowed. I really liked that feature and had thought I had it working on lenses that were AF but could also MF. Reading the manual seems to state otherwise - that I need to keep the camera in AF mode.

Maybe I mounted it wrong and had the electrical contacts blocked for AF. Is this not possible with my Pentax-F AF and DA lenses?

Also, is it possible to change the lowest ISO in auto ISO?

08-15-2009, 10:46 PM   #2
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You do have to stay in AF mode since in MF mode, you can trip the shutter with subject not in focus.

The trap focus works best with MF lenses since AF mode for those just means that you can trip the shutter only when subject is in focus. If you're using an AF lens, you will have to block the little shaft that does autofocus (look at your camera mount, around 5 o'clock). You might want to try putting a small piece of aluminum foil there, so that your AF lens effectively becomes an MF lens.

Also, I'm not sure about min ISO in auto ISO. If you think about it, setting min ISO isn't really that necessary, since the lower the ISO, the less noise and more detail - while camera still maintains an appropriate shutter speed.
08-15-2009, 11:36 PM   #3
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The reason I want to set the min ISO is to pseudo-emulate TAv mode for action shots. I don't want my lens to be wide open because it is not as sharp there if it is in Tv mode with Auto ISO, nor do I want it to be stopped down too far because I want a smaller DOF, and I find I can do this with setting the ISO within limits. However, I also don't want to manually set the ISO for when it does get very dark and very bright during the day (clouds)

As for trap focus - does AF mode on camera mean the shutter can only activate when in focus? I tried disabling AF with half shutter press / making the AF button cancel AF so it doesnt even move the AF while in AF mode but it was still taking out of focus pictures.
08-16-2009, 12:53 AM   #4
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QuoteQuote:
The reason I want to set the min ISO is to pseudo-emulate TAv mode for action shots. I don't want my lens to be wide open because it is not as sharp there if it is in Tv mode with Auto ISO, nor do I want it to be stopped down too far because I want a smaller DOF, and I find I can do this with setting the ISO within limits. However, I also don't want to manually set the ISO for when it does get very dark and very bright during the day (clouds)
Eh... I don't really have anything to say here. On other models with front wheels,you just rotate front wheel.

QuoteQuote:
As for trap focus - does AF mode on camera mean the shutter can only activate when in focus? I tried disabling AF with half shutter press / making the AF button cancel AF so it doesnt even move the AF while in AF mode but it was still taking out of focus pictures.
Eh, not really. Here's how it goes. There are two "procedures" you can make camera do - activate autofocus, and trip the shutter. In any mode, the "trip shutter" command trips the shutter - regardless of any reason *except* if you have no memory left, or if camera buffer is full, or if you ran out of battery.
Now, autofocus "procedure" focuses your lens until image is in focus, and then freezes - and if the image is not focused, it will not let the first procedure work (so, in AF mode, until the small green hexagon appears on the screen, you cannot trip the shutter). If your lens is MF, this "procedure" simply sits there and checks if the image is in focus; if it is, it shows the hexagon, and lets the shutter go if you press the button, if the image is not in focus, it will not let shutter trip.
So... If you make AF button cancel AF, when you press it, you're simply deactivating the AF "procedure" - so shutter will go even if image is not in focus. When you are half-pressing the shutter release, you're simply activating the AF "procedure" (obviously in your case, if you're pressing the AF button - which is mapped to *cancel* AF, AF won't activate). When you push it in fully, you're still running the AF "procedure", but now you want the camera to take the picture, BUT since you're still running the first "procedure", camera will NOT take the picture until image is in focus.
Now, I do really hope I didn't make that too confusing. If you need help, just say so.

Bo.

08-16-2009, 01:56 AM   #5
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QuoteOriginally posted by pbo Quote
Eh... I don't really have anything to say here. On other models with front wheels,you just rotate front wheel.
Eh... This defeats the purpose of what I want - I don't want to rotate anything, I want to keep the lens on the action - hence my comparison with TAv mode and not Tv mode and the front dial. On this camera I can hit one button and then rotate the e-dial to get the same effect then snap a picture, which is more than simple enough on every other shot except action shots.
QuoteQuote:
Eh, not really. Here's how it goes. There are two "procedures" you can make camera do - activate autofocus, and trip the shutter. In any mode, the "trip shutter" command trips the shutter - regardless of any reason *except* if you have no memory left, or if camera buffer is full, or if you ran out of battery.
Now, autofocus "procedure" focuses your lens until image is in focus, and then freezes - and if the image is not focused, it will not let the first procedure work (so, in AF mode, until the small green hexagon appears on the screen, you cannot trip the shutter).
You just contradicted yourself - you did not list the green hexagon as a reason to not trip the shutter. I understood that in the first post but if you really read my post you would realize that my shutter trips without the green hexagon in AF mode.
QuoteQuote:
If your lens is MF, this "procedure" simply sits there and checks if the image is in focus; if it is, it shows the hexagon, and lets the shutter go if you press the button, if the image is not in focus, it will not let shutter trip.
So... If you make AF button cancel AF, when you press it, you're simply deactivating the AF "procedure" - so shutter will go even if image is not in focus.
So here you correct yourself - above you say in AF mode, you can't trip the shutter without the green hexagon. Please try to be more consistant.
QuoteQuote:
When you are half-pressing the shutter release, you're simply activating the AF "procedure" (obviously in your case, if you're pressing the AF button - which is mapped to *cancel* AF, AF won't activate). When you push it in fully, you're still running the AF "procedure", but now you want the camera to take the picture, BUT since you're still running the first "procedure", camera will NOT take the picture until image is in focus.
You really did not need to attempt to explain it in more detail as it has become even harder to follow. I understood your previous post as "AF mode for those just means that you can trip the shutter only when subject is in focus. " which well simply wasn't true. That statement is why I attempted the cancel / disable AF in AF mode.

So now that I know it will not work in this camera - is this feature available on any other pentax camera? or any other brand?

Last edited by Eruditass; 08-16-2009 at 09:20 AM.
08-16-2009, 12:03 PM   #6
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The only AF lenses that work with trap focus are ones that have an AF/MF switch on the lens itself. That way, the camera can be set to AF but the lens can be set to MF. I think this feature was new wiht the K20D; not sure if it's on the K2000. Mostly, trap focus is for manual focus lenses only, as the whole idea requires the camera switch to be in AF but not to actually focus the lens. Since the camera is in AF mode, the shutter won't fire until the subject is in focus, and since the lens won't focus automatically, it just sits there waiting for you to turn the ring or something to move in the frame.

As for setitng a lower bound on ISO in auto ISO mode, I don't think it's possible - it's not on the K200D or any other single-dial models.
08-16-2009, 01:49 PM   #7
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QuoteQuote:
You just contradicted yourself - you did not list the green hexagon as a reason to not trip the shutter. I understood that in the first post but if you really read my post you would realize that my shutter trips without the green hexagon in AF mode.
QuoteQuote:
So here you correct yourself - above you say in AF mode, you can't trip the shutter without the green hexagon. Please try to be more consistant.
Please try to be more patient and read into it instead of nitpicking. Maybe you'll understand faster that way.

QuoteQuote:
"AF mode for those just means that you can trip the shutter only when subject is in focus. " which well simply wasn't true.
It is true. Assuming you're not pressing dedicated AF button, whenever you press the shutter, you also half-press the shutter, correct? So, you're activating AF by half-pressing the release button - thus not allowing the shutter go with image out of focus. That's assuming if you're not cancelling AF yourself by pressing dedicated AF button.
IF you are pressing that AF button, which on your camera is mapped to cancelling AF - then what are you complaining about? You cancelled AF yourself, so it's not working, and it's not checking if your image is in focus!

QuoteQuote:
So now that I know it will not work in this camera - is this feature available on any other pentax camera? or any other brand?
It will work. It will work on any Pentax camera.
The needed ingredients are: a camera and a MF lens. If you want it to work remotely, then also a wired release.
The half-press for AF in Custom options has to be set on ON. AF mode has to be set on AF or whatever you got there on K2000. NO MF, trap focus won't work in MF mode. (just in case, the lever for controlling that option is located on camera body just right of lens mount)

NOW mount a K-Mount MF lens onto the camera. If you don't have an MF lens, you will have to somehow block the autofocus shaft that's protruding from camera's mount at about 5 o'clock position. I'd suggest first trying to use a small piece of aluminum foil. Hint if you can't find the shaft - it looks like a flat screwdriver's tip, and it protrudes out of camera's body when you set AF mode to AF, and it goes back inside when you set camera to MF.

Now, put your camera in continuous shooting mode. Defocus your lens. Press shutter. Did it work? If so, read everything again.

If not, congratulations! That's how it's supposed to be on any camera regardless of brand, make, whatever.
08-16-2009, 05:47 PM   #8
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QuoteOriginally posted by pbo Quote
Please try to be more patient and read into it instead of nitpicking. Maybe you'll understand faster that way.
I just didn't appreciate your condescending tone with "Eh.." followed by something that doesn't relate to the question and "If you need help, just say so." Why do you think this thread exists?

I understand how it works after being led in the wrong direction by your first post.
QuoteQuote:



It is true. Assuming you're not pressing dedicated AF button, whenever you press the shutter, you also half-press the shutter, correct? So, you're activating AF by half-pressing the release button - thus not allowing the shutter go with image out of focus. That's assuming if you're not cancelling AF yourself by pressing dedicated AF button.
Canceling AF allows you to take a picture when the subject is not in focus and the green hexagon is not lit. So literally you can take a picture when the subject is not in focus in AF mode. This is what threw me off, as I am a very literal and logical person. This of course assumes you don't make some arbitrary definition of what the subject is and that by pushing the AF button to cancel or disabling AF, that the subject is already in focus (although you can get away with saying it assumes the subject is in focus but I don't like to think that cameras make assumptions.)
QuoteQuote:
IF you are pressing that AF button, which on your camera is mapped to cancelling AF - then what are you complaining about? You cancelled AF yourself, so it's not working, and it's not checking if your image is in focus!
Thank you for not understanding the point of this thread. If you did, you would understand what I am "complaining" about. It would be kinda nice and not break any logical functions if the trap-AF custom setting allowed this.
QuoteQuote:



It will work. It will work on any Pentax camera.
The needed ingredients are: a camera and a MF lens. If you want it to work remotely, then also a wired release.
Are you serious? Do you not see me asking in the first post if it will work with non-MF lenses? I know it will work with MF lenses, hence why I had it working in the beginning.
QuoteQuote:
The half-press for AF in Custom options has to be set on ON. AF mode has to be set on AF or whatever you got there on K2000. NO MF, trap focus won't work in MF mode. (just in case, the lever for controlling that option is located on camera body just right of lens mount)
Thank you for writing this out, it's not like I read the manual as I stated in the OP.
QuoteQuote:

NOW mount a K-Mount MF lens onto the camera. If you don't have an MF lens, you will have to somehow block the autofocus shaft that's protruding from camera's mount at about 5 o'clock position. I'd suggest first trying to use a small piece of aluminum foil. Hint if you can't find the shaft - it looks like a flat screwdriver's tip, and it protrudes out of camera's body when you set AF mode to AF, and it goes back inside when you set camera to MF.
Thank you for repeating this as if I didn't read it the first time. Or if I didn't allude to it in the OP by saying maybe I blocked the electrical contacts because I already know that is one method to doing it.
QuoteQuote:

Now, put your camera in continuous shooting mode. Defocus your lens. Press shutter. Did it work? If so, read everything again.

If not, congratulations! That's how it's supposed to be on any camera regardless of brand, make, whatever.
Thanks..

So anyone else care to answer my question on whether or not any camera make or model will do trap-AF with a lens that is stuck in AF without blocking electrical contacts?

As for no minimum Auto-ISO, I guess that is the one main thing I will miss from a K20d and the D90 I used. It really helps because I hate how Tv mode selects the max aperture! my lenses aren't that good, they need to be stopped down! However, my M42 adapter isn't here let so we'll see how well metering works without optical preview.


Last edited by Eruditass; 08-16-2009 at 06:16 PM.
08-17-2009, 05:11 AM   #9
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QuoteOriginally posted by Marc Sabatella Quote
The only AF lenses that work with trap focus are ones that have an AF/MF switch on the lens itself. That way, the camera can be set to AF but the lens can be set to MF. I think this feature was new wiht the K20D; not sure if it's on the K2000.
It's available and works exactly the same on K-m/K2000

Eruditas: for the auto ISO thing, why not just set a "high enough for action, low enough minimize noise" ISO value, e.g. ISO400 and raise it when you need even higher shutter speeds? You can change ISO with the wheel without taking away your face from the viewfinder if ISO was the last setting you changed on control screen: just hit OK and rotate the wheel, you can see the actual values in the viewfinder (assuming you enabled it in custom settings). It's not a perfect solution and no substitute for TAv mode, but I think it's as close as it can be.
08-17-2009, 07:20 AM   #10
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This is what I am currently doing - but it is a little hard with some action outside when clouds come in and out but sometimes the slower / faster shutter speed variation gives my shots a little variety!

edit: actually it is a little easier - if I didn't adjust ISO last, I just have to hit the right d-pad button and have instant access to it, quite nifty.

Last edited by Eruditass; 08-17-2009 at 10:07 AM.
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